This Wynorski sequel picks up with a reprise of the finale from the previous entry, with the death of Andrew Stevens and his screenwriting friend... so it pays attention to continuity. To a point. Number three had a need coda where Dr Archer got away with the murder and a film was made of it starring Morgan Fairchild - that's thrown away, which is disappointing as I kind of liked it.
Instead Archer is on trial for the producer's murder. Unable to stop getting up to her old tricks, she seduces her defence attorney. Like in 3, the guy is married.
However the script isn't as strong as 3 - in that one the wife had a real goal, to be in the film of Archer's life; here she gets a few phone calls and nags the lawyer (Larry Poindexter) about never coming come. Also in the previous one there was a good subplot about the screenwriter investigating - the one here, where Poindexter's assistant is wondering what's going on, isn't as good.
They do reprise the characters of the two film executives - Robert Forster doesn't return in his part (they get some silver fox to do it) but Stella Stevens does.
Larry Poindexter is a bit wet in the lead - he doesn't have Stevens' strength. However Shannon Tweed is great value as Archer, much better than the girl in three, as she seduces Poindexter on several occasions. It copies most of the story beats of the third film, though you can understand why - they work.